High-uniformity coloured polyester industrial yarn

Abstract

A high uniformity coloured polyester industrial yarn and preparation method. The raw material of the high-uniformity coloured polyester industrial yard is the modified polyester composed of terephthalic acid segment, an ethylene glycol segment and a branched diol. The high-uniformity coloured polyester industrial yarn is prepared by esterification reaction of terephthalic acid with a branched diol using concentrated sulfuric acid as catalyst to obtain terephthalic acid glycol ester. Terephthalic acid and ethylene glycol are formulated to carry out esterification reaction to obtain ethylene terephthalate. Finally, stir and mix the two materials and carry out the polycondensation reaction in the low vacuum stage and the high vacuum stage under the action of the catalyst and the stabilizer to obtain modified polyester. Measure the modified polyester and add black masterbatch. After porous spinneret extrusion, cooling, oiling, drawing, heat setting and winding the modified polyester, high uniformity coloured polyester industry yarn is obtained.

What is claimed is: 
     
       1. A high-uniformity coloured polyester industrial yarn, wherein
 the high-uniformity coloured polyester industrial yarn is a polyester industrial yarn added with a black masterbatch, 
 the high-uniformity coloured polyester industrial yarn is obtained by spinning after carrying out a solid phase polycondensation, 
 the high uniformity coloured polyester industrial yarn comprises a modified polyester, wherein the modified polyester is composed of a terephthalic acid segment, an ethylene glycol segment and a branched diol segment, the branched diol segment is a diol having a branched chain, the branched chain is a non-terminal carbon on the branched diol segment and the branched chain has a linear carbon chain containing 5 to 10 carbon atoms, 
 the high-uniformity coloured polyester industrial yarn has a breaking strength ≥7.0 cN/dtex, a linear density deviation rate ≤1.0%, and a breaking strength CV value ≤2.0%; 
 a CV value of elongation at break is ≤5.5%, a melt viscosity of the high uniformity coloured polyester industrial yarn is reduced by 10-20% at a temperature of 260-290° C.; and 
 when a test condition is 177° C.×10 min×0.05 cN/dtex, a dry heat shrinkage ratio is 2.5±0.5%, and a melt viscosity drop is a comparison of the melt viscosity of the modified polyester and a polyester without the branched diol segment at a same temperature. 
 
     
     
       2. The high uniformity coloured polyester industrial yarn according to  claim 1 , wherein
 the high-uniformity coloured polyester industrial yarn has an elongation at break of 12.0±1.5%; a number average molecular weight of the modified polyester ranges from 15,000 to 30.000. 
 
     
     
       3. The high-uniformity coloured polyester industrial yarn according to  claim 1 , wherein
 the branched diol segment is one or more items selected from the group consisting of a 2-pentyl-1,3 propanediol segment, a 2-hexyl-1,3 propanediol segment, a 2-heptyl-1,3 propanediol segment, a 2-octyl-1,3 propanediol segment, a 2-pentyl-1,4 butanediol segment, a 2-hexyl-1,4 butanediol segment, a 2-heptyl-1,4 butanediol segment, a 2-octyl-1,4 butanediol segment, a 2-pentyl-1,5 pentanediol segment, a 2-hexyl-1,5-pentanediol segment, a 2-heptyl-1,5-pentanediol segment, a 2-octyl-1,5-pentanediol segment, a 2-pentyl-1,6 hexanediol segment, a 2-hexyl-1,6 hexanediol segment, a 2-heptyl-1,6-hexanediol segment, and a 2-octyl-1,6-hexanediol segment; 
 and a molar percentage of the branched diol segment to the ethylene glycol segment ranges from 2% to 5%. 
 
     
     
       4. A method for preparing the high-uniformity coloured polyester industrial yarn of  claim 1 , wherein the modified polyester is subjected to the solid phase polycondensation, metering, and adding the black masterbatch;
 after porous spinneret extrusion by a porous spinneret, cooling, oiling, drawing, heat setting and winding to obtain the high uniformity coloured polyester industrial yarn; 
 the arrangement of the orifices on the porous spinneret is elliptical; the elliptical arrangement means that the centers of the orifices are located on concentric ellipses, and the concentric ellipses are a series of ellipses, and the long axes of all the ellipses are collinear, and the short axes of all the ellipses are collinear; 
 a method for preparing the modified polyester includes the following steps: 
 (1) preparation of terephthalic acid glycol ester: 
 mixing terephthalic acid and the branched hexanediol to a first slurry, and carrying out a first esterification reaction under a catalytic action of concentrated sulfuric acid to obtain the terephthalic acid glycol ester; 
 (2) preparation of ethylene terephthalate: 
 mixing the terephthalic acid and ethylene glycol to a second slurry, carrying out a second esterification reaction to obtain the ethylene terephthalate; 
 (3) preparation of the modified polyester: 
 after the second esterification reaction in the step (2) is completed, adding the terephthalic acid glycol ester prepared in the step (1), stirring and mixing, performing a polycondensation reaction under the action of the catalyst and the stabilizer, and under a condition of a negative pressure; first in a low vacuum stage and then in a high vacuum stage to obtain the modified polyester. 
 
     
     
       5. The method for preparing the high-uniformity coloured polyester industrial yarn of  claim 4 , wherein, in the method for preparing the modified polyester
 the first slurry in the step (1) is added to a first reactor for carrying out the first esterification reaction; the first esterification reaction is carried out under a pressurized nitrogen environment, and the pressure is in a range of a normal pressure to 0.3 MPa, and a temperature is 180-240° C.; the first esterification reaction ends when a water distillation amount in the first esterification reaction reaches at least 90% of a first theoretical value; then the terephthalic acid glycol ester is obtained; 
 the second slurry in the step (2) is added into a second reactor for carrying out the second esterification reaction; the second esterification reaction is carried out under a pressurized nitrogen environment, and the pressure is in a range of normal pressure to 0.3 MPa, and a temperature is 250-260° C.; the second esterification reaction ends when a water distillation amount in the second esterification reaction reaches at least 90% of a second theoretical value; then the ethylene terephthalate is obtained; 
 in step (3) the stirring and mixing is performed for 15-20 minutes under the action of the catalyst and the stabilizer, and the negative pressure; in the polycondensation reaction under the condition of the low-vacuum stage, the pressure is smoothly pumped from the normal pressure to an absolute pressure under 500 Pa, a temperature is controlled at the temperature of 260-270° C., and a reaction time is 30-50 minutes; then turn to the high vacuum stage, the polycondensation reaction continues and the reaction pressure is reduced to an absolute pressure of less than 100 Pa, and the reaction temperature is controlled at the temperature of 275 to 280° C., and the reaction time is 50 to 90 minutes in order to obtain the modified polyester; 
 obtaining modified polyester chips by granulate the modified polyester and carrying out the solid phase polycondensation of the modified polyester chips in order to make an inherent viscosity of the modified polyester increase to 1.0-1.2 dL/g to form a high-viscosity chip; after measuring, adding the black masterbatch, the extrusion of porous spinneret, cooling oiling, stretching, heat setting and winding, the high-uniformity coloured polyester industrial yarn is obtained; 
 a mass ratio of the black masterbatch to the modified polyester chips ranges from 0.01%-0.03%; 
 spinning process parameters of the high-uniformity coloured polyester industrial yarn are as follows: 
 an extrusion temperature is 290-320° C.; 
 a wind temperature is 20-30° C.; 
 a winding speed is 2600-3200 m/min. 
 
     
     
       6. The method for preparing the high-uniformity coloured polyester industrial yarn of  claim 5 , wherein, in step (1), a molar ratio of the terephthalic acid to the branched diol is 1:1.3-1.5; an amount of the concentrated sulfuric acid added is 0.3-0.5% of a weight of the terephthalic acid; a concentration of concentrated sulfuric acid is 50-60 wt %;
 in step (2), a molar ratio of the terephthalic acid to the ethylene glycol is 1:1.2-2.0; 
 in step (3), a molar percentage value of the diol terephthalate and the ethylene terephthalate is 2-5%; the catalyst is antimony trioxide, antimony glycol or antimony acetate, and an amount of catalyst added is 0.01%-0.05% of the total weight of the terephthalic acid; the stabilizer is triphenyl phosphate, trimethyl phosphate or trimethyl phosphite, and an amount of stabilizer added is 0.01%-0.05% of the total weight of the terephthalic acid; 
 a number average molecular weight of the modified polyester ranges from 15000-30000. 
 
     
     
       7. The method for preparing the high-uniformity coloured polyester industrial yarn according to  claim 5 , wherein the branched diol is one or more selected from the group consisting of a 2-pentyl-1,3 propanediol, a 2-hexyl-1,3 propanediol, a 2-heptyl-1,3 propanediol, a 2-octyl-1,3 propanediol, a 2-pentyl-1,4 butanediol, a 2-hexyl-1,4 butanediol, a 2-heptyl-1,4 butanediol, a 2-octyl-1,4 butanediol, a 2-pentyl-1,5 pentanediol, a 2-hexyl-1,5-pentanediol, a 2-heptyl-1,5-pentanediol, a 2-octyl-1,5-pentanediol, a 2-pentyl-1,6 hexanediol segment, a 2-hexyl-1,6 hexanediol, a 2-heptyl-1,6-hexanediol, and a 2-octyl-1,6-hexanediol. 
     
     
       8. The preparation method of the high uniformity coloured polyester industrial yarn according to  claim 4 , wherein the spinneret is a circular spinneret or an elliptical spinneret; a difference between a diameter of the circular spinneret and a maximum length of the long axis of the series ellipse is greater than 10 mm, and a difference value between the elliptical spinneret and the maximum length of the long axis of the series ellipse is greater than 10 mm. 
     
     
       9. The preparation method of the high-uniformity coloured polyester industrial yarn according to  claim 4 , wherein the arrangement of the spinneret holes is long axis and/or short axis symmetry; a ratio of the length the long axis of the ellipse to the length of the short axis of the ellipse ranges from 1.3-1.8; a spacing of the adjacent spinneret holes is greater than a diameter of a guide hole of the spinneret hole plus 1.5 mm. 
     
     
       10. The method for preparing a high-uniformity coloured polyester industrial yarn according to  claim 9 , wherein the guide hole diameter of the spinneret ranges from 1.5-2.5 mm; the number of spinneret holes is greater than or equal to 192, and the cross-section shape of the spinneret spinning hole is a circle, square, diamond, linear shape, triangle, trilobal shape, hollow type or flat type. 
     
     
       11. The method for preparing a high-uniformity coloured polyester industrial yarn according to  claim 4 , wherein the high-uniformity coloured polyester industrial yarn has an elongation at break of 12.0±1.5%; a number average molecular weight of the modified polyester ranges from 15,000 to 30,000. 
     
     
       12. The method for preparing a high-uniformity coloured polyester industrial yarn according to  claim 4 , wherein the branched diol segment is one or more items selected from the group consisting of a 2-pentyl-1,3 propanediol segment, a 2-hexyl-1,3 propanediol segment, a 2-heptyl-1,3 propanediol segment, a 2-octyl-1,3 propanediol segment, a 2-pentyl-1,4 butanediol segment, a 2-hexyl-1,4 butanediol segment, a 2-heptyl-1,4 butanediol segment, a 2-octyl-1,4 butanediol segment, a 2-pentyl-1,5 pentanediol segment, a 2-hexyl-1,5-pentanediol segment, a 2-heptyl-1,5-pentanediol segment, a 2-octyl-1,5-pentanediol segment, a 2-pentyl-1,6 hexanediol segment, a 2-hexyl-1,6 hexanediol segment, a 2-heptyl-1,6-hexanediol segment, and a 2-octyl-1,6-hexanediol segment;
 and a molar percentage of the branched diol segment to the ethylene glycol segment ranges from 2% to 5%.